 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
DP8417D-80 Datasheet(PDF) 8 Page - National Semiconductor (TI) |
|
|
||||||||||||||||||||||||||||||
DP8417D-80 Datasheet(HTML) 8 Page - National Semiconductor (TI) |
|
|
8 / 28 page  Mode Features Summary Y 4 modes of operation 2 access and 2 refresh Y Automatic or external control selected by the user Y Auto access mode provides RAS row to column change and then CAS automatically Y Choice between two different values of tRAH in auto-ac- cess mode Y CAS controlled independently in external control mode allowing for nibble mode accessing Y Automatic refreshing can make refreshes transparent to the system Y CAS is inhibited during refresh cycles DP8419 Mode Descriptions MODE 0 – EXTERNALLY CONTROLLED REFRESH Figure 2 shows the Externally Controlled Refresh timing In this mode the refresh counter contents are multiplexed to the address outputs All RAS outputs are enabled to follow RASIN so that the row address indicated by the refresh counter is refreshed in all DRAM banks when RASIN goes low The refresh counter increments when RASIN goes high RFSH should be held low at least until RASIN goes high (they may go high simultaneously) so that the refresh address remains valid and all RAS outputs remain enabled throughout the refresh A burst refresh may be performed by holding RFSH low and toggling RASIN until all rows are refreshed It may be useful in this case to reset the refresh counter just prior to begin- ning the refresh The refresh counter resets to all zeroes when RFIO is pulled low by an external gate The refresh counter always counts to 511 before rolling over to zero If there are 128 or 256 rows being refreshed then Q7 or Q8 respectively going high may be used as an end-of-burst indicator In order that the refresh address is valid on the address outputs prior to the RAS lines going low RFSH must go low before RASIN The setup time required is given by tRFLRL in the Switching Characteristics This parameter may be ad- justed using Figure 10 for loading conditions other than those specified TABLE III DP8419 Mode Select Options Mode (RFSH) M2 M0 Mode of Operation 0 0 0 Externally Controlled Refresh 1 0 1 Auto Refresh – Forced 4 1 0 Externally Controlled Access 5 1 1 Auto Access (Hidden Refresh) 8 |
Similar Part No. - DP8417D-80 |
|
Similar Description - DP8417D-80 |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
